The present invention relates to a hydraulic hybrid transmission, the transmission comprising a hydraulic circuit including a hydraulic pump and two hydraulic displacement units in fluid communication with the hydraulic pump, and further comprising a hydraulic accumulator assembly in fluid communication with the hydraulic circuit. Hydraulic hybrid transmission systems of this sort may find application in off-highway working machines used in agriculture, mining or construction, such as tractors, wheel loaders, wheeled excavators, backhoe loaders, telehandlers, dumpers, or the like.
The present application claims priority from U.S. Provisional Patent Application No. 61/935,642 filed on Feb. 4, 2014, which is hereby incorporated by reference in its entirety.
All hybrid powertrain systems reduce fuel consumption by recuperating kinetic energy and by enabling engine power buffering (for example, through optimal management of a powertrain operating point). For example, a series hydraulic hybrid arrangement as known is characterized by a pressure coupling of an accumulator and main lines, which means that boosting and regeneration are possible only when the accumulator pressure is consistent with the powertrain operating conditions (external load and speed).